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Is Evolution a Dangerous Idea? If so, why?

 
 
cicerone imposter
 
  1  
Reply Mon 22 Jul, 2019 10:46 pm
@edgarblythe,
From my perspective, none of us living today has to worry about that final phbttt.
0 Replies
 
brianjakub
 
  1  
Reply Tue 23 Jul, 2019 03:02 pm
@farmerman,
Quote:
what is a second defined as?


Quote:
the historical definition of the unit was based on this division of the Earth's rotation cycle, the formal definition in the International System of Units (SI) is a much steadier timekeeper: it is defined by taking the fixed numerical value of the caesium frequency ∆νCs, the unperturbed ground-state hyperfine transition frequency of the caesium 133 atom, to be 9192631770 when expressed in the unit Hz, which is equal to s−1.[1][2] Because the Earth's rotation varies and is also slowing ever so slightly, a leap second is periodically added to clock time[nb 1] to keep clocks in sync with Earth's rotation.

Quote:
Were there many clocks around during the Pleistocene? the Cambrian?[

Yes, it has been scientifically verified that it is highly probable there were caesium 133 atoms (as well as other atoms) during the Pleistocene and the Cambrian. The question is was the frequency the same as it is today because the amount of disorder in matter determines the gravitational constant and gravity effects the frequency . (Which is understood by the scientific community and factors into the calibration of clocks on gps satellites.

Why do you ask?
farmerman
 
  1  
Reply Tue 23 Jul, 2019 05:51 pm
@brianjakub,
put it in your own words and Ill let you know if youre close to understanding.

I used to claim deposits of pollucite in culm banks of lepidolite and spodumene.
Why do you think cesium 133 was the second obvious SI candidate defining the second?.

(The math only works when we can see that a compilation of (X)femto seconds defines the age of a specific iron nickel meteorite containing U238)
brianjakub
 
  1  
Reply Wed 24 Jul, 2019 11:42 am
@farmerman,
Quote:
put it in your own words and Ill let you know if youre close to understanding.


The timekeeping element in every modern clock is a harmonic oscillator (a physical object that vibrates or oscillates at a particular frequency). The object can be a pendulum, a tuning fork, a quartz crystal, or the vibration of electrons in atoms as they emit microwaves. Atoms give off energy in packets that radiate at a very specific and consistent frequency. So, every atom is a clock because they are made up of particles that move in a systematic way.
Quote:
Why do you think cesium 133 was the second obvious SI candidate defining the second?.


The technical explanation to why cesium 133 is the most accurate element to build an atomic clock is hard to picture but the interaction between the electron cloud and nucleus in cessium is more consistent than any other atom. So since the mechanism of an atomic clock is contained in the electron cloud there is a small range of error even in cessium.

Quote:
(The math only works when we can see that a compilation of (X)femto seconds defines the age of a specific iron nickel meteorite containing U238)


And the point of that statement is?
0 Replies
 
 

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